As implantable electrical devices have increased in their complexity, there have been an increasing variety of lead systems developed for use in conjunction with these devices. Nowhere is this more apparent than in the context of implantable cardioverter/defibrillators and biventricular IMDs to treat congestive heart failure. These IMDs require the use of three or more leads. The leads themselves may carry one, two, three (or more) electrodes, and may employ a variety of different electrical connector configurations and types. As a result, manufacturers of such devices have had to produce their products with a variety of connector block configurations, capable of use with different lead systems. For example, Medtronic, Inc. presently manufactures implantable cardioverter/defibrillators with four basic connector designs, designated configurations “B,” “C,” “D,” and “E.” The “B” configuration includes three 6.5 mm connector ports for receiving high voltage electrical lead connectors of the type used to couple to cardioversion/defibrillator electrodes and one 3.2 mm in-line electrical connector port compatible with the IS-1 connector standard for receiving an IS-1 electrical lead connector of the type generally used to couple to cardiac pacing and sensing electrodes. The “C” configuration includes a single 3.2 mm connector bore conforming to the DF-1 standard for receiving high voltage electrical lead connectors for coupling to cardioversion/defibrillation electrodes. This configuration also includes a single IS-1 connector bore. The “D” configuration includes three DF-1 connector bores and one IS-1 connector bore. The “E” configuration includes two 6.5 mm connector bores and two 5 mm connector bores for receiving electrical lead connectors used to couple to individual cardiac pacing and sensing electrodes.
As is apparent from the above discussion, multiple connector block types are necessitated both by the use of multiple connector standards, and also because of the desire to connect a varying number of lead systems used for specific purposes to a given device. The situation is complicated even further by the use of non-standard connector systems. For example, it has been increasingly common to utilize small-diameter guide catheters to deliver leads having a diameter of 7 French or less to a desired implant site.
With the increased use of multi-chamber pacemakers and defibrillators such as those that provide bi-atrial or bi-ventricular pacing capabilities, multiple leads are required to deliver electrical stimulation to various locations within the heart. With the use of multiple leads that are positioned within one or more small vessels of the body, it has become even more important to minimize lead and lead connector size. As leads become smaller, it becomes increasingly difficult to connect these small diameter leads to and within the connector block of an IMD during an implant procedure. In addition, it also becomes increasingly difficult to mark these smaller diameter leads with the appropriate identification, including manufacturer identification and/or lead model and serial numbers.
The issue of marking and/or identifying small diameter lead has been addressed in several ways in the art. The following patents are exemplary of the plurality of approaches: U.S. Pat. No. 5,824,030 to Yang, U.S. Pat. No. 5,374,279 to Duffin, U.S. Pat. No. 4,628,934 to Pohndorf, U.S. Pat. No. 6,085,118 to Hirschberg, U.S. Pat. No. 5,300,120 to Knapp, U.S. Pat. No. 5,833,603 to Kovacs, U.S. Pat. No. 5,423,334 to Jordan and U.S. Pat. No. 5,252,962 to Urbas. While the above publications teach various improvements to the art, they do not address the problems of identifying small diameter leads or of coupling non-standard, small diameter leads to header module of an IMD.